By american



Aug. 30. 1927.

' R 16,729 G. M. RUSSELL AUTOMATIC MUSICAL INSTRUMENT Origi l Filed Dec.26, 1917 2 6 I 8 f cIIJIKI/ LD 3 6 56 .1? 72 45 42 34 4 44% as; 47 8 I lIi 48 v I 49 Reissued Aug. 30, 1927 UNITED STATES Re. 16,729 PATENTOFFICE,

v GUY MANLY RUSSELL, DECEASED, LATE OF SYRACUSE, NEW YORK; BY AMERICANPIANO COMPANY, or Nnw'YonK, N. Y ASSIGNEE.

AUTOMATIC MUSICAL INSTRUMENT.

Original mi. 1,409,497, dated March 14, 1922, Serial No. 208,758, filedDecember 26, 1917. Application for reissue filed March 12, 1924. SerialNo. 698,783.

This invention relates to automatic means for playing'musicallnstruments such, for

nstance, .as' pianos; and pertains more particularly to means forgoverning and varymg tone intensities.

The principal object of the invention is.

i to provide apparatus capable of producing ings show diagrammaticallyone practicable a great number of variations in intensity of playing;such apparatus comprising preferably, though not essentially, acombination of means for producing crescendo and diminuendo efiectsandalso for instituting various defined grades or'ste'ps of playingintensities. 1

For illustration the accompanying drawembodiment of the inventionemploying suitable pneumatically governed devices in cooperation with apiano action; but as will appear to those skilled in the art, theinvention is susceptible of embodiment in various constructions andorganizations other than that particularly shown and described herein.It will be equally apparent that all thefeatures of the invention neednot be used conjointly, since their respective advantages may accruefrom their separate application in any practicable manner to a suitableinstrument.

The drawings consist of a diagrammatic representation of a portion of atypical player action with operating and governing means exemplifyingthe application and utility ofthe invention.

In the drawings a striker or player pneumatic l is provided, having asticker 2 to' act upon a wippen 8 and thereby operate the usual pianoaction, as well understood in the art. A wind trunk 4 leads to a windchest 5 forthe player pneumatics, each of which I has a secondary valve6 controlled by a primary valve 7 which is operated from a tracker board8 through a duct .9 in the usual manner.

The wind trunk 4 communicates with the interior of'a reservoir bellows10. An exhaust pump '11 constitutes a main source of power and isdirectly connected with the reservoir bellows 10 by a duct 12. Theexhaust pump may be driven by an electric motor 13. For convenience the;exhaust pump and motor are shown on a greatly reduced scale and it willof course be understood that' any suitable exhausting appara tus,whether power driven or not may be employed in carrying out theinvention.

The bellows 10 has a stationary board 14 and a movable board 15. movableboard is a spring 16 which at its outer end is fast to an adjustingscrew 17 threaded in a fixed abutment 18. The reservoir bellows isprovided with a relief valve 19 cooperating with a port 20 opening tothe bellows and herein conveniently located in the movable board 15. Thevalve 19 is threaded upon a valve stem 21 and supported bya'suitable'bracket 22. A light spring 23 tends normally to hold thevalve 19 against its seat. i V

.In operation the pump'll tends to exhaust air from the bellows 10, fromthe wind trunk 4, and-the wind chest 5 with which the play- .erpneumaticsare connected selectively. It

will be readily understood by those skilled scribed.

Apparatus embodying this invention may have a three-fold capacity forcontrolling the valve 19 and the consequent degree of exhaust within thewine chest 5. The apparatus may perform a regulating function, that isit may maintain any given playing intensity whether one or many notes besounded; it may produce automatically continuously progressive changesin playing intensities for crescendo and diminuendo purposes; and it mayproduce automatically incremental changes in pla *ing intensities.

These three capacities of the apparatus will be described in thesequence indicated.

The bellows apparatus previously referred to is herein shown mountedwithin the reservoir bellows 10 and preferably attached to its fixedboard 14. It comprises a bellows 25 having a movable board 26 hinged tothe fixed board of the reservoir bellows 10, and a number of bellowsattached to the movable board 26 of the bellows 25. Herein are shownthree bellows 27 28 and 29 separated Attached to the 19 it may beassumed that the bellows 27, 28 and 29 are open to atmosphere and itwill later appear a degree of exhaust with- IRS in the wind chest 5 willthereby be estab bellows apparatus will tend to hold the four bellows25, 2'7, 28 and 29 in fully expanded position. As the reservoir bellowscollapses the stem 21 will bear against the board 32 of the bellows 29and hold the valve so that upon further collapse of the reservoirbellows atn'iosphere will be admitted through the port 20. hen thisopening of the port 20 takes place the tension of the s n'i'ng willsubstantially equal the force provided by the differential between theexhaust and atmosphere acting upon the area of the board 15. Therefore,by proper adjustment of the valve upon its stem or of the spring throughits adjusting nut, a normal minimum degree of exhaust may beestablished. I

During the playing of the instrument atmosphere is being admi ted invarying amounts, principally by the operation of the player pneumaticswhich when at rest contain atmosphere. To maintain the pressuresubstantially uniform the admission of atmosphere through the playerpn-eumatics may be compensated by a corresponding lessening of theamount of atmosphere being admitted past the valve 19. A sudden influxof atmosphere through the player pneu-v matics may cause a momentaryslight decrease in the pressure within the reservoir bellows. Thisslight decrease will permit the board 15 to move toward the va zethusclosing slightly the atmosphere port. This in turn will cause the pumpto take a relatively larger amount of air from the wind chest 5 andthereby restore the normal mini mum degree of exhaust. The reservoirbellows and its valve respond so quickly to minute fluctuations ofexhaust wit n the wind chest 5, that the effect is maintain the degreeof exhaust than to re store it, as will be readily understood by thoseskilled in the art.

Having described the regulating functions of the apparatus, the meansfor producing crescendo and diminuendo effects will now be described.

It will be readily understood by those skilled in the art that if anyone of the ex- 25,pression pneumatics 25, 27, 28 or 29 is 001- lapsedthe pumping mechanism will establish a higher degree of exhaust withinthe reservoir and also within the. wind chest 5 before the valve 19 canoperate to admit atmosphere. This results, in the specific construct-ionshown, from a movement of the abutment 32 toward the fixed wall of thereservoir bellows and necessitates afurther movement of the movableboard toward the fixed board 14 before the stem 21 of the valve willcontact with the abutment 32. This movement of the board 15 elongatesthe spring 16 thereby increasing its. pull upon the board 15 andnecessitating a greater differential between exhaust and atmosphere toovercome and balance this increased pull.

For crescendo and diminuendo purposes the pneumatic is herein selected.The interior of this pneumatic, which may be termed a crescendopneumatic, is connected by a duct 33 with a valve box 34. Ducts 35 and36 connecta wind chest 37 within the valve box 34 with the wind trunk 4so that this wind chest 37 is always in communication withthe interiorof thereservoir bellows 10. The duct 33 is connected with the channel 38in the valve box which leads to a. valve chamber 39 having a port 40 toatmosphere and a port 41 to the exhaust chamber 37 A valve 42 is mountedwithin the valve chamber 39 and its stem rests upon a diaphragm 43covering a diaphragm chamber 44. The usual bleed is provided in this andsimilar 'diaphragms. A duct 45 leads from this diaphragm chamber to avent 45 in the tracker bar 8. In the channel 38 are two obstructionscrews 46 and 47, of which the screw 46 restricts the channel 38 to agreater extent than the screw 47. A by-pass 48 is provided, which whenopen permits the passage of air around the obstruction screw 46. Aby-pass valve 49 is mounted upon a diaphragm 50 over a diaphragm chamber51. This diaphragm chamber isconnected by a channel 52 with a valvechamber 53 having a port- 54 to atmosphere and a port 55 to the exhaustchamber 37. A valve 56 is mounted in the valve chamber 53 and its stemrests upon a diaphragm 58 covering a diaphragm chamber 57. Thisdiaphragm chamber is connected by a duct 59 with a vent 59 in thetracker bar 8.

As the parts are shown in the drawings,

the crescendo pneumatic 25 is open to atmosphere through the duct 33,channel 38 atmosphere port 40. If the valve 42 is operated to close theatmosphere port 40 and open the exhaust port 41, as for instance, by theopening of the tracker vent 45' by the note sheet, the pneumatic 25 willbe placed in communication with reservoir bellows 10. Connecting thepneumatic 25 with he reservoir bellows 10 will tend to equalize thepressures upon opposite sides of the board 26 and initiatea collapsingmovement of the pneumatic 25 due to the slight pres-' sure of the spring23 through the valve stem 21. -This results'in a partial closing of thevalve 19, a reduction inthe amount of atmosphere drawn through the portand a consequent slight increase in the degree of exhaust within thereservoir bellows 10.

This increaseis accompanied by a further increase within the pneumat1c25and a further collapse of the reservolr bellows.

' This action will continue until the pneupany a slow decrease-in thede.

matic is fully collapsed. The communication between the pneumatic 25 andreservoir bellows 10, in the described operation,

is restricted by the obstruction gscrew 4 7 which provides the greaterrestriction, This restriction in communication willreta'rd theequalizing of pressures within the pneumatic 25 and bellows 10 so thatthe collapsing movement of the pneumatic 25 willbe slowed up and theconsequent increase of the degree of BXl'AELUSt WltlHH the bellows' l0accomplished slowly at a speed appropriateto a slow crescendo.

y A slow diminuendc, which will .ac coing e or exhaust within bellows10, may be accomplished by admitting atmosphere slowly to pneumatic 25as for instance by the closing of exhaust port lland the opening ofatmosphere port 40' by the valve 42. Thls valveoperation may beinitiated by closing the tracker vent The apparatus thus has thecapacity ofproducing a slow crescendo and'a slow diminuendo. To providefor faster crescendo and diminuendo operations the valve 56 may beappropriatelyv operated to by-pass the obstruction screw 46, which maybe conveniently called the slow crescendo adjustment screw, while 47 maybe called the fast crescendo adjustment screw. For example, if a fastcrescendo is desired the tracker ducts 45 and .59 may be simultaneouslyopened thereby operating valves 42 and 5G simultaneously; the result ofoperation of "alve 42 being to connect the pneumatic 25 with theinterior of the reservoir bellows 10 and the result of operation of thevalve being to by-pass obstruction screw 46 and thus enlarge theeffective openmg of the channel 38.

As will be readily understood by those skilled in the art, a crescendomay be started at one speed and changed to another speed intermediateits extreme limits; a fast diminuendo mayfollow a slow crescendo andvice versa and other varying combinations of crescendo and diminuendoeffects can be produced.

Having sufficiently described the regulating functions of the apparatus,the crescendo and diminuendo functions, the manner of r producingincremental intensity changes will now be described.

g It is desirable to have'the apparatus capable of producingsubstantially instantaneous incremental changes, of varying degrees, inplaying intensities. For this purpose the pneumatics 2'7, 28, and 29 areutilized. These pneumatics'are of different sizes arranged so that th ymay be collapsed individually or in combination to effect their separateor'combined results as presently described.

A description of the operationof one of these pneumatics, for instancepneumatic 27, will suflice for all. The interior of pneumatic 27 isconnected by a fleftible duct 69. a nipple 61, a duct 62 and a channelto with avalve chamber G l havin a port 65 to atmosphere and a port 66to an exhaust chamberfili. This exhaust chamber is connected by a duct68, a duct 69, the duct 35 and the wind trunk 4 with the interior imounted within the valve: chamber 74 and r rests upon a'diaphragm 78over a diaphragm chamber 7 9. The diaphragm chamber 7 9 is connected bya duct 80, with a tracker vent correspondingly numbered. The parts lastdescribed are duplicated for pneumatics 28 and 29 and bear thesamenumbcrs with indices a andV) respectively.

' In describing the operation of the pneumatics 27, 28 and 29 it will beassumed that atmosphere is present at. all times in the crescendopneumatic '25. If the tracker vent 80 is opened to admit atmosphereunder the diaphragm 7 8, the valve 77 will be operated to close exhaustport 76and open atmosphere port 75 thus admitting atmosphere to thechannel 73 and to the diaphragm chamber 72. The admission of atmosphereto this diaphragm chamber will operate valve 70 to close atmosphere port65 and open ez zhaust port 65 thus placin the pneumatic 27 incommunication with the interior of the reservoir bellows 10. Thiscommunica tion between the pneumatic 27 and the reservoir bellows 10,beingvfree and unrestricted the pressure within pneumatic 28 will beequalized. with the pressure in the reservoir bellows 10 substantiallyinstantaneously and will inaugurate a collapsing movement of thepneumatic 27' in the manner previously described in connection withpneumatic 25, with the exception that the complete collapse of pneumatic2'? will be attained substantially instantaneously.

This quicltcollapse of the pneumatic 27 will be accompanied by a quickcolla )se of the reservoir bellows and a corresponding are increase inthe degree of exhaust therein and in the wind chest 5 to increaseplaying intensities by a substantially distinct increment. Upon closingthe tracker vent 80, atmosphere will he suddenly admitted to thepneumatic 2.7 and it will tend to open the valve 19 thus permitting aquick expansion of the reservoir bellows and a consequent suddendecrease in the degree of exhaust therein.

It will be readily understood that the extent of this incremental changein playing intensity will bear a certain relation to the extent ofmovement of the pneumatic 27. If, therefore, pneumatics 28, and 29 areof a diiferent size, incremental changes of different extents may besecured by the separate collapse of any of these bellows. It will alsobe understood that the bellows may be collapsed in varying combinationsthereby providing a substantial range of incremental intensity changes.

It is desired that the maximum degree of exhaust which may beinaugurated by the crescendo mechanism be substantially the same as themaximum degree of exhaust attainable by step change mechanism andtherefore the movement of the abutment 32, by the collapse of thecrescendo pneumatic 25, is made substantially the same as its movementupon collapse of all three expression pneumatics 27, 28 and '29.

It is also desirable that the incremental intensity change mechanism andthe crescendo mechanism be operable concurrently so that a crescendoeffect may be superposed upon an existing incremental effect or a noteor notes may be accented during the progress of a crescendo. To providefor this and to prevent the apparatus from exceeding the maximum a fixedarm 81 is mounted within the reservoir bellows and a collar 82 isthreaded upon the valve stem 21. The collar 82 may be so adjusted uponthe valve stem that it will come in contact with the arm 81 when thedesired maximum degree of exhaust has been attained.

It will be readily understood by those skilled in the art how thesuperposing of expression effects may be accomplished by appropriateperforations in the note sheet. For example, if it is desired to accenta note during a slow crescendo any one or all of the pneumatics 27, 28and 29 may be suddenly opened to the reservoir bellows 10 and atmosphereadmitted again without disturbing the slow collapse of the pneumatic 25.Similarly if it is desired to start a crescendo from some intermediatestep attained for instance by the collapse of pneumatic 27, thecrescendo pneumatic 25 may be opened to the reservoir bellows and theabutment 32 will be slowly moved until the stop 82 comes in contact withthe arm 81 when the maximum playing intensity has been attained. Manyother and varied effects may be attained singly or in combina tion aswill be understood by those skilled in the art.

It is to be understood that the invention shown in the diagrammaticconstruction of the drawings, may be variously modified and embodiedwithin the scope of the subjoined claims. y

I claim as my invention:

1. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power foroperatingthe playingpneumatics; a reser voir bellows having constant communicaionwith the main source of power and the wind chest for the playingpneumatics; and

crescendo means within the reservoir bellows automatically operating tovary the action of said reservoirbellows to produce a substantiallycontinuous progressional change in playing intensities for crescendopurposes.

2. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a governor bellows having unrestrictedcommunication with the main source of power and the wind chest for theplaying pneumatics; a tracker; and a tracker controlled crescendopneumatic to vary the action of said governor bellows to produce asubstantiallv continuous progressional change in playing intenslties forcrescendo purposes.

3. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operating.the playing pneumatics; a governor bellows having unrestrictedcommunication with the main' source of power and the wind chest for theplaying pneumatics; crescendo means to vary the action of said governorbellows to produce a substantially continuous progressional change inplaying intensities for crescendo purposes; and speed governing meansfor the crescendo means.

4. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a governor bellows having unrestrictedcommunication with the main source of power and the wind chest for theplaying pneumatics; a tracker; a tracker controlled crescendo pneumaticto vary the action of said governor bellows to produce a substantiallycontinuous progressional change in playing intensities for crescendopurposes; and tracker controlled speed governing means for the crescendopneumatic.

5. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a governor bellows having unrestrictedcommunication with the main source of power and the wind chest for theplaying pneumatics;

the wind chest for the playing pneumatics;

a tracker; and tracker controlled expression means to vary the action ofthe governor bellows by substantially distinct increments for producingintensities. In an automatic musical instrument the combination ofplaying pneumatics; a wind chest therefor; a main source of power foroperating the playing pneumatics; a reservoir bellows provided with aport to atmosphere and having constant communication incrementalvariations in playing with the main source of power and the wind chestfor the playing neumatics; a valve to control admission of atmosphere tosaid reservoir bellows; an abutment against which said valvenormallybears; and means to move said abutment slowly toproducecrescendo effects in playing intensities.

.8. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a. main source of power for operatingtheplaying neumatics; a reservoir bellows provided with a port toatmosphere and having constant communication with the main source ofpower and the wind chest for the playingpneuma'tics; a valve to controladmission of atmosphere to said reservoir bellows; an. abutment againstwhich said valve normally bears; a tracker; and tracker'controlled meansto move said abutment slowly .to produce c'rescendo effects in playingintensities. 7

9. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe laying neumatics; a reservoir bellows provi ed with a port toatmosphere and havmg. constant communication with the main source ofpower andthe wind chest for the playing penunratics; a valve to controladmission" of atmosphere to said reservoir bellows; an abutment againstwhich said valve normally bears; and means to move said abutmentsuddenly to produc e incrementalrchanges in playing intensitles.

10. In an automatic musical instrument the combinat-ion of playingPneumatics;- a

wind chest therefor; amain source of power for operating theplayerpneumatics; ares-- ervoir bellows provided .with a port to atforoperating the playing mosphere and having constant communication withthe main source of power'and the wind chest for the playing pneumatics;a valve to control admission of atmosphere to said reservoir bellows; anabutment against which said valve normally bears; a tracker; and trackercontrolled means tomove said abutment suddenly to produce incrementalchanges in playing intensities.

11. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main sourceof power for operatingthe playing pneumatics; a reser-, voir bellows having constantcommunication with the main source of power and the wind chest for theplaying pneumatics; a valve to control admission of atmosphere to saidreservoir bellows; an abutment againstwhich said valve normally bears;means to move said abutment slowly to produce crescendo effects inplaying intensities; and

means to move said abutment suddenly to produce incremental changes inplaying in tensities. v o v v 12. In an automatic musical instrument thecombination of playing pneumatics; 'a wind chest therefor; a main sourceof power 'pneumaties; areservoirbellows having a port to atmosphere andconnected to the wind chest for the playing pneumatics; a valvecontrolling said atmosphere port to said reservoir bellows; a valvegoverning pneumatic mounted within said reservoir bellows; and means toplace said pneumatic in communication with said reservoir bellows tovary playing intensities. V

13. In an automatic musical instrument the combination of playingpneumatics"; a wind chest therefor; a main source of power for operatingthe playing pneumaticsya reservoir bellows. having va port toatmosphereand connected to the wind chest for the playing pneumatics; avalve controlling said atmosphere port to said reservoir bellows; avalve. governing crescendo pneumatic mounted within said reservoirbellows; and means to place said pneumatic in communicationwith, saidreservoir bellows through .a restricted opening.

I 14. In an automatic musical instrument the combination ofplayingPneumatics; awind chest therefor; a main source of power foroperatingthe playing pneumatics; a reservoir bellows having a port toatmosphere and connected to the wind chest for the playing pneumatics avalve controlling said atmosphere port to said reservoir bellows; orvalve governing crescendo pneumatic mount ed within said'reservoirbellows; means providing restricted connections of different capacitiesfrom said pneumatic to said reservoir bellows; and means for selectivelycontrolling said connections.

15. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a ervoir bellows having a port to atmospher andconnected to the wind chest for the playing pneumatics; a valvecontrolling said atmosphere port to said reservoir bellows; a valvegoverning pneumatic mounted within said reservoir bellows; a tracker;and tracker controlled means to place said pneumatic in communicationwith said reservoir bellows to carry playing intensities.

16. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a reservoir bellows having a port to atmosphereand connected to the wind chest for the playing pneumatics; valvecontrolling said atmosphere port to said reservoir bellows; a valvegoverning crescendo pneumatic mounted within said reservoir bellows; atracker; and tracker controlled means to placesa'id pneumatic incommunication with said reservoir bellows.

17 In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a re:- ervoir bellows having a port toatmosphere and connected to the wind chest for the playing pneumatics; avalve controlling said atmosphere port to said reservoir bellows; avalve governing crescendo pneumatic mounted within said reservoirbellows; means providing restricted connections of different capacitiesfrom said pneumatic to said reservoir bellows; a tracker; and trackercontrolled means for selectively opening and closing said connections.

18. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a'main source of power for operatingthe playing pneumatics; a reservoir bellows having a port to atmosphereand connected to the wind chestfor the playing pneumatics; a valvecontrolling said atmosphere port to said reservoir bellows; a pluralityof valve governing pneumatics mounted within said reservoir bellows; andmeans for selectively connecting said pneumatics with said reservoirbellows.

19. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a resc voir bellows having a port to atmosphereand connected to the wind chest for the playing pneumatics; a valvecontrolling said atmosphere port to said res-ervoir bellows; a pluralityof valve governing pneumatics mounted within said reservoir bellows; atracker; and tracker controlled means for selectively connecting saidpneumatics with said reservoir bellows.

20. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a reservoir bellows having a port to atmosphereand connected to the wind chest for the playing pneumatics; a valvecontrolling said atmosphere port to said reservoir bellows; a pluralityof valve governing pneumatics having diiferent extents of movementmounted within said reservoir bellows; and means forselectivelyconnecting said pneumatics with said reservoir bellows.

21. In' an automatic musical instrument the combination of playingpneumatics; a wind chest therefor; a main source of power foroperatingthe playing pneumatics; a reservoir bellows having a port toatmosphere and connected to the wind chest for the playing pneumatics; avalve controlling said atmosphere port to said reservoir bellows; aplurality of valve governing pneumatics having difi'erent extents ofmovement mounted within said reservoir bellows; a tracker; and trackercontrolled means for selectively connecting saidpneumatics withsaidreservoir bellows.

22. In an automatic musical instrument the combination of playingpneumatics; a wind chest therefor a main source of power for operatingthe playing pneumatics; a reservoir bellows having a port to atmosphereand connected to the wind chest for the play-' ing pneumatics; a valvecontrolling said atmosphere port to said reservoirbellows; a pluralityof valve governing pneumatics mounted within said reservoir bellows;means to connect one of said pneumatics with said reservoir bellowsthrough a restricted opening to produce crescendo effects in playingintensities; and means to connect other of said pneumatics selectivelywith said reservoir bellows throughunobstructed openings to produceincremental elfects in playing intensities.

23. In an automatic musical instrument, the combination of playing,pneumatics; a wind chest therefor; a main source of power for operatingthe playing pneumatics; a

governor bellows having unrestricted communication with the main sourceof" power and the wind chest for the playing pneumatics; a tracker; anda tracker controlled expression means to vary the action of the governorbellows by substantially distinct increments for producing incrementalvariations in playing intensities and also to produce a substantiallycontinuous progressive change in playing intensities for crescendopurposes. I

24. In an automatic musical instrument the combination of a wind chest;a main source of power; a governor bellows having unrestrictedcommunication with the main source of power and the wind chest; and eX-llii) pression means automatically operating to vary the action of thegovernor bellows by substantially distinct increments for producingincremental variationsof pressure in thewind chestL.

25. In an automatic musical instrument the combination of a wind chest;a main source of power; a governor bellows having unrestrictedcommunication with the main source of power and the wind chest; andtracker controlled expression means to vary the action of the governorbellows by substantially distinct increments for producing incrementalvariations of pressure in the wind chest.

26. In an automatic musical instrument having the usual playingpneumaticsan d main source of power, in combination, a

wind chest; a reservoir bellows having communication with atmosphericairand con-' nected to the wind chest; a valve controlling saidcommunication with atmospheric air; a valve governing pneumatic: andmeans to place said pneumatic in communication with said reservoirbellows to vary playing intensities.

27. In an automatic musical instrument having the usual playingpneumatics and a main source of power, in combination, a wind chest; areservoir bellows having communication with atmospheric air andconnected to said wind chest: a valve controlling said communicationwith atmospheric air; a valve governing pneumatic; a tracker; and

tracker controlled means to place said pneumatic in communication'withsaid reservoir bellows to vary playing-intensities.

"28. In an automatic musical instrument having the usual playingpneumatics and a main source of power, in combination, a wind chest; areservoir bellows having communication with atmospheric air andconnected to said wind chest: a valve controlling said communicationwith atmospheric air; a plurality of valve governing pneumatics: andmeans for selectively connecting said pneumatics with said reservoirbellows.

29. In an automatic musical instrument having the usual playingpneumatics and a main source ofpower, in combination, a wind chest; areservoir bellows having communication with atmospheric air andconnected to said wind chest: a valve controlling said communicationwith atmospheric air; a plurality of valve governing pneumatics havingdifferent extents of movement; and

means for selectively connecting said pneumatics with said reservoirbellows.

30. In an automatic musical instrument having the usual playingpneumatics and a main source of power, in combination, awind chest; areservoir bellows having communication with atmospheric air andconnected to said wind chest: a valve controlling said communicationwith atmospheric air;

and a plurality of valve governing pneumatics having different extentsof movement; a tracker; and trackercontrolled means for selectivelyconnecting said pneumatics with said reservoir bellows.

31'. Iii-combination with a musical'instrument having playing pneumaticsand a source of power, means to govern the action of'the source of powerincluding a pneumatic, means providing a port to atmosphere, awalve forsaid port controlled by the movable board of said pneumatic andsupplementary tracker controlled pneumatics for varyingthe actionof'said first-named pneumatic upon said valve. i

32. In an automatic musical instrument, having a wind chest and a mainsource of power, in combination, a regulator bellows having unrestrictedcommunication with the main source of power and wind chest and adaptedto maintain pressures therein at a substantially constant level; atracker; and tracker controlled pneumatic means to vary the operation ofsaid regulator to cause it to maintain pressures in said wind chestvarying by predetermined increments.

33. In an automatic musical instrument, having a wind power, incombination, a chamber having communication with the wind chest andsource of power and having a movable wall responsive to changes ofpressure therein; a port through which atmospheric air may be admittedto said chamber; a valvecontrolling said port; means whereby movement ofthe movable wall afiects the valve to thereby maintain a. predeterminedpressure in'the system at a substantially constant level; and pneumaticmeans for varying said lastnamed means to cause the position of themovable wall to be changed whereby the pressure maintained in the systemis changed.

34:. Expression controlling mechanisms for musical instruments havingplayer pneu matics and a mainsource of power, including, in combination,an exhaust chamber having a port providing communication between saidchamber and atmosphere, a valve controlling said port, a pneumaticcontrol ling said valve, and a plurality of supplementary pneumatic-sfor varying the action of said first-named pneumatic on said valve tovary exhaust in said exhaust chamber by perceptible increments.

35. Expression controlling mechanisms for musical instruments havingplayer pneumatics and a main source of power, including. in combination.an exhaust chamber having a port providing communication be tween saidchamber and atmosphere, a valve controlling said port, a pneumaticcontrolling said valve, and a plurality of supplementary pneumaticshaving different extents of movement for varying the action of saidpneumatic on said valve to vary exhaust in chest and a main source ofsaid exhaust chamber byperceptible increment's.

Expression controlling mechanisms-for musical instruments having player.pneumatics and a main source of power, including, in combination, anexhaust chamber having a port providing communication between saidchamber and atmosphere, a valve controlling said port, a pneumaticcontrolling said valve, a plurality of supplementary pneumatics forvarying the action of said first-named pneumatic on said valve to varyexhaust in said exhaust chamber by perceptibleincrcments, a tracker, andvalves controlled by said tracker to control the operation of saidsupplementary pneumatics.

37. Expression controlling mechanisms for musical instruments havingplayer pneumatics and a main source of power, including, in combination,an exhaust chamber having a port providing communication betweensaidchamber and atmosphere, a valve controlling said port, a pneumaticcontrolling said valve, a plurality of supplementary pneumatics havingdifferent extents of movement for varying the action of said first namedpneumatic on said valve, a tracker, and valve devices controlled by saidtracker for selectively operating said suphaving a port providingcommunication beplementa'ry pneumatics to vary exhaust in said exhaustchamber by perceptible increments.

38. Expression controlling mechanismsfor musical instrun'ients havingplayer pneumatics and a main source oi power, including, in combination,an exhaust chamber tween said chamber and atmosphere, a valvecontrolling said port, a pneumatic controlling said valve, a pluralityof supple-mentary pneumatics having d'iiierent extents of movement forvarying the action of said first named pneumatic on said valve, atracker, and tracker controlled means for operating one of saidsupplementary pneumatics to vary exhaust in said exhaust chamber by apredetermined increment, and tracker controlled devices for operating adiiierent supplementary pneumatic to vary exhaust in said chamber by adifferent increment.

In testimony whereof, this specification has been signed this 10th dayof March, 1924.

AMERICAN PIANO COMPANY, A sir nee of Guy Mcmly Russell, Deceased.

By 1. E. EDGAR,

- Trees.

